With the recent rapid spread of information processing-related devices and communication devices such as personal computers, video cameras, and mobile phones, importance placed on developments of batteries used as power sources for the above-mentioned devices has been increasing. Further, in the industry fields such as automobile industry, developments of batteries having high output and high capacity for electric vehicles or hybrid cars have been made. Currently, lithium batteries are attracting attentions from a viewpoint that they have high energy density among the various batteries.
The lithium batteries currently available in the market use a liquid electrolyte containing a flammable organic solvent. As such, they require installation of a safety device to inhibit the temperature rise at the time of short circuit or improvement in technical structure or materials to inhibit short circuit. In contrast thereto, a lithium battery having its battery all solidified by changing the liquid electrolyte to a solid electrolyte layer does not use a flammable organic solvent in the battery. Accordingly, it is possible to simplify the safety device and thereby thought to be good in production cost and productivity.
As the ion conductor (solid electrolyte material), an ion conductor having a spinel structure is known. The spinel structure is a structure represented by a general formula AB2X4, in which “X” is an anion of 16th and 17th group elements (such as O2−, S2−, and Cl−); “B” is a metal cation provided to an octa-hedral site (such as Al3+, Mn3+, and Ti4+); and “A” is a metal cation provided to a tetra-hedral site (such as Li+, Mg2+, Zn2+.
Active researches have been made on the ion conductor having the spinel structure. For example, Patent Document 1 discloses the ion conductor which is represented by Li2xZn1−x(Al2)O4. Further, an ion conductor which has an inverse-spinel structure is known. For example, Non-Patent Documents 1 to 3 disclose the ion conductor containing Cl− as an anion.